Windshield washer fluid, and other automotive fluids, such as radiator coolant or engine oil, typically are sold in plastic jugs of a size convenient to the consumer. In the case of windshield washer fluid, such jugs typically contain a gallon of fluid, and currently sell at a retail price of roughly $1.25 per gallon (slightly more in some places, slightly less in others). Such fluid is relatively cheap to produce--typically it consists simply of a water/methanol mixture, with about 10-35% methanol, depending on the climate in which the product is sold (the higher methanol percentage is desirable in colder climates). Thus, a significant portion of the retail cost of windshield washer fluid lies in the cost of producing, filling and capping the plastic jug, and transportation costs associated with distribution and handling of the plastic jugs.
In the northern states which have snowy climates, retail sales of windshield washer fluid can be extremely erratic, being highly dependent upon weather conditions. Road spray on highways during and after a snowfall, particularly on roads that have been salted and sanded by highway crews, can cause motorists to use fairly large quantities of fluid in a short amount of time. The spring melting of snow along highways can also give rise to dirty road spray. These types of weather conditions create spikes of demand for windshield washer fluid, as motorist in some weather conditions may actually need to use a squirt of washer fluid every mile or even half-mile. In contrast, very cold and dry conditions, or consistently warm and dry conditions, do not give rise to such high levels of demand.
Although retail outlets of all types sell windshield washer fluid, service stations in particular sell large quantities of this fluid during the winter months in northern states. Some service stations can sell hundreds of gallons per day in certain weather conditions. Yet, retail "floor space," whether indoors or out, is usually fairly limited in such service stations. Thus, the stocking of service stations with gallon jugs of windshield washer fluid becomes a labor intensive, challenging job, as demand can be very heavy for a few days or weeks, and then very light for until weather conditions again cause high demand. Yet, it is very important for retailers, particularly service stations, to not run out of fluid during high demand days, as a very large portion of annual sales of windshield washer fluid occur on a proportionately small number of such days.
Other areas of the country experience similar erratic demand cycles for windshield washer fluid. In some states there are seasonal periods during which bugs are an inordinate problem. For example, Florida typically has a bug season of about one month in duration both spring and fall; during those seasons windshields become regularly fouled with particularly messy bugs, creating a much larger than normal demand for windshield washer fluid. Thus, in these periods of time the high demand for windshield washer fluid creates inventory control challenges.
In addition to the challenges of cost-effective inventory control for such automotive fluids, the use of plastic jugs to distribute such fluid creates environmental disposal concerns. Even though windshield washer fluid is mostly water, the plastic gallon jugs in which the fluid is sold generally are not re-usable. Thus, each year large numbers of such jugs must be either land-filled or, where available, recycled.
Self-service vending of automotive fluids from a coin-operated dispensing unit has been proposed for certain applications. For example, U.S. Pat. No. 5,497,914 shows a car care self-service device designed to dispense small quantities of a number of different types of cosmetic car care fluids, such as engine cleaner, rubber cleaner, windshield and glass cleaner, windshield washer fluid, upholstery cleaner, air fresheners, or the like. The user inserts in a predetermined amount of money, and then selects which type of fluid is desired. A corresponding hose/nozzle is then activated to permit the user to dispense a small quantity of the chosen fluid. This vending unit is mounted on casters, so that it can be rolled around, and, thus, while the system is capable of dispensing measured amounts of various types of fluids, the system plainly is not designed to handle the relatively enormous volume of windshield washer fluid (e.g., hundreds of gallons) that a typical service station might sell on a particularly high-demand day.